Continuously loaded conductor



P 1936. M; K. ZINN CONTINUOUSLY LOADED CONDUCTOR I Filed Sept. 12, 1934INVENTOR MEZWII/ ML ATTORNEY Patented Sept. 15 1936 UNITED STATESCONTINUOUSLY LOADED CONDUCTOR Manvel Keeport Zinn, Brooklyn, N. Y.,assignor to American Telephone and Telegraph Company, acorporation ofNew York Application September 12, 1934, Serial No. 743,766

8 Claims. (01. 178-45) My invention relates to continuously loadedconductors and more particularly to a method of making such a conductorstable, so that the variation of its inductance with the strength ofcurrents sent over it is miminized.

A continuously loaded conductor is one in which the distributedinductance is increased by surrounding -the conductor with magneticmaterial, as in the form of a wrapping of tape or in the form of a solidsheath continuously deposited by electrolytic means. Continuously loadedconductors are useful for various situations in telephone practice,particularly in connection with submarine cables.

One difficulty encountered in the use of some continuously loadedconductors is that the inductance Varies too much with the strength ofcurrents sent over the wire. This is particularly true as regardsrelatively large direct currents used for operating, testing andsignaling purposes.

An object of my invention is to reduce this variability of theinductance. The method of attaining this object may be understood by thefollowing disclosure of examples of practice of the invention, havingreference to the accompanying drawing.

Figure 1 is a curve diagram to which reference will be made indiscussing the principles involved in the invention; Fig. 2 is adiagrammatic elevation of a conductor of my invention in process ofmanufacture; Fig. 3 is a diagrammatic crosssection of a modified form ofa conductor of. my invention, and Fig. 4 is a diagrammatic, longitudinalsection of yet another modification.

On Fig. 1, curves I and 2 represent the variation of the permeability oftwo different types of magnetic material with the strength of themagnetizing force in the materials. Since, as is well known, theinductance of a continuously loaded conductor is directly proportionalto the permeability of the magnetic material, the inductance of aconductor loaded with either of these materials would vary in proportionto the permeability variations shown. This amount oi.

variability might make either of these two materials undesirable as aloading material to be applied continuously on the conductor. Bycombining both materials on the same conductor,

however, it is possible to reduce the range of the permeabilityvariation to that represented by curve 3. Curve 3 has been drawn for anequal mixture of the materials whose permeability variations are shownby curves I and 2, but in the case of particular materials, some otherproportion of mixing might be more desirable. More than two materialscould be combined on the same conductor to reduce the variability of theinductance still further. It is rather common for a given. simplematerial to yield a peaked 5 characteristic, curve like ,I or 2 inFig. 1. Curve 3 of that figure averages the corresponding ordinates of Iand 2; Hence a desired curve like 3 with a fiat top over a certain rangecan generally be secured by choice of two suitable materials 10 havingcurves with peaks at the respective ends of that range.

The two or more types of magnetic material to be placed on the conductormay be combined in several ways: They may be placed in successive 15layers on the conductor or they may be applied in sequence alongsuccessive short lengths of the conductor. In the latter case, it isimportant that the interval over which each type of material is appliedshall be short enough to avoid selective transmission effects resultingfrom reflection of electric waves at the junctions of the differenttypes of loading.

The desired differences in the permeability characteristics of thevarious materials to be combined can be produced by variations incomposition, in heat treatment or in mechanical Working. With magneticmaterials comprising nickel-iron alloys this can be accomplishedreadily, because the magnetic properties of these alloys 30 areparticularly sensitive to suchdifierences in treatment.

In Fig. 2, a simple conductor 4 is covered with a shell formed bywrapping the tape 5 closely around it in a helical course. Then anothertape 6 is wrapped outside 5 in the same way. The material of tape 5corresponds to curve I or 2 of Fig. 1 and the material of the other tape6 corresponds to the other curve 2 or I of Fig. 1.

In Fig. 3, one material 5 is electro-plated over 40 the core 4 and theother material 6 is electroplated over that. I

In Fig. 4, the two materials are plated in longitudinal alteration, thatis, a certain length is plated with material 5", then a length with 6",45 then 5", and so on in alternation.

What I claim is:

1. A continuously loaded electric conductor in which the loadingmaterial comprises two or more different materials, said materials beingapplied 50 in periodic sequence to successive lengths of the conductor.

2. A continuously loaded electric conductor in which the loadingmaterial comprises two or more different materials, said materials being55 the permeability of one material is relativelyhigher than that ofanother while at another magnetizing force the permeability of saidother material is relatively higher than that of said first material.

4. A conductor consisting of a core ductive material surrounded by twomaterials, each material having a peaked curve of permeability plottedagainst magnetizing force, these curves being such that the curve ortheir average ordinates is if'lattopped.

" 5. conductor consisting of a core of conducti ve matria surrounded bytwo materials having approiiimately the same average permeability ever arangof magnetizing forces, but one mae terial having a permeabilityconsiderably higher of the other at one forcevalue and of conthe othermaterial having a permeability considerably higher than that of thefirst material at another force value.

6. A continuously loaded electric conductor in which the loadingmaterial comprises two or more different materials, said materials beingapplied along the length of the conductor to successive portions thereofeach in alternation with the other or others.

7. The method of establishing uniform permeability in a loaded electricconductor which consists in establishing decreasing permeability withincreasing magnetizing force in a part of the loading, and establishingincreasing permeability with increasing magnetizing force in anotherpart of the loading whereby the resultant permeability is substantiallyuniform.

8 A conductor consisting of a core of conductive material, anelectroplated sheath surrounding it and having a certain permeability-WQQQF QQS iQlQ ha acteris c. 5!?( a oth elee rqp e eq hea h surr u di gth first mentime; Sh ath e l havin a d f ere Prim shi iyaa snei z i9???eha eq eri tia the re ul'tant nat on Qt h o characteristics a ring lmierm Permeabi ity wi h maanet i lpa force.

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